/Engine/Source/Runtime/CoreUObject/Public/UObject/PackageResourceManager.h
Only works on PackagePaths with PackageName, will fail on unmounted LocalOnly paths. Will fail if the instance has not been initialized or if another instance has already registered for the PackagePath. Return whether the instance is currently registered. Returns true if the instance was already registered. Registered files are referenced-counted, and the reference will not be dropped until TryTakePreloadableArchive or UnRegister is called
True if and only if the archive is now registered for the packagepath, False if the packagepath could not be registered or a different archive was already registered
static bool TryRegisterPreloadableArchive ( const [FPackagePath](API\Runtime\CoreUObject\Misc\FPackagePath) & PackagePath, const [TSharedPtr](API\Runtime\Core\Templates\TSharedPtr)< [FPreloadableArchive](API\Runtime\Core\Misc\FPreloadableArchive) > & PreloadableArchive, const [FOpenPackageResult](API\Runtime\CoreUObject\UObject\FOpenPackageResult) & PackageFormat )